This application claims the priority of Korean Patent Application No. 2003-10040, filed on Feb. 18, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The invention relates to a method and apparatus of driving an image display device, such as, a plasma display panel (PDP) for representing gradation on the image display device.
2. Description of the Related Art
FIG. 1 shows a conventional method of gradationally driving a panel. The conventional method of FIG. 1 is disclosed in U.S. Pat. No. 5,541,618. A panel driving time can be divided into a reset (initialization) period, an address (writing) period, and a sustain (display) period. During the reset period (not shown), each cell of the panel is initialized to facilitate smooth cell addressing. In FIG. 1, the address periods are indicated by a dotted area and during the address periods wall charges are accumulated on the cells which are to be lit later. The sustain periods are indicated by hatched areas and during the sustain period discharging occurs to display a picture on the addressed cells.
As shown in FIG. 1, to achieve gradation with a frame-subfield structure, separate address periods and sustain periods are driven independently over time. In other words, during each subfield, after all of the scan electrodes, Y1 to Yn, are completely addressed, all pixels undergo sustaining simultaneously.
Accordingly, when gradation is achieved according to such a conventional panel-driving method, a significant time gap may exist between the time when a cell undergoes addressing and the time when the cell undergoes sustain discharging. This leads to unstable sustain discharging.